Analysis of chlorine forms in hard coal and the impact of leaching conditions on chlorine removal

2020 ◽  
Author(s):  
Izabela Mazurek ◽  
Agnieszka Skawińska ◽  
Marcin Sajdak
Keyword(s):  
Hard Coal ◽  
Chlorine Removal ◽  
The Impact

The Influence of Disintegration of Hard Coal Varieties of Different Metamorphism Grade on the Amount of Sorbed Ethane / Wpływ rozdrobnienia odmian węgla kamiennego o różnym stopniu metamorfizmu na ilości sorbowanego etanu

2013 ◽  
Vol 58 (2) ◽  
pp. 449-463 ◽  
Author(s):  
Mieczysław Żyła ◽  
Agnieszka Dudzińska ◽  
Janusz Cygankiewicz
Keyword(s):  
Sorption Isotherms ◽  
Electron Donors ◽  
Hard Coal ◽  
Coal Surface ◽  
Compact Layer ◽  
Compact Structure ◽  
Small Surface ◽  
Mining Works ◽  
The Impact ◽  
Content Of Oxygen

Ethane constitutes an explosive gas. It most often accompanies methane realizing during exploitation and mining works. In this paper the results of ethane sorption have been discussed on three grain classes of six selected hard coal samples collected from active Polish coalmines. On the basis of obtained results, it has been stated that the tested hard coals prove differentiated sorption power with reference to ethane. Te extreme amount of ethane is sorbed by low carbonized hard coal from “Jaworzno” coalmine. This sort of coal shows great porosity, and great content of oxygen and moisture. The least amount of ethane is sorbed by hard coal from “Sośnica” coalmine. This sort of coal possesses relatively a great deal of ash contents. Together with the process of coal disintegration, the amount of sorbed ethane increases for all tested coal samples. Between tested coals there are three medium carbonized samples collected from “Pniówek”, “Chwałowice” “Zofiówka” coalmines which are characterized by small surface values counted according to model BET from nitrogen sorption isotherms determined at the temperature of 77.5 K. The samples of these three coals prove the highest, from between tested coals, increase of ethane sorption occurring together with their disintegration. These samples disintegrated to 0,063-0,075 mm grain class sorb ethane in the amount corresponding with the sorption quantity of low carbonized coal from “Jaworzno” coalmine in 0.5-0.7 mm grain class. It should be marked that the low carbonized samples collected from “Jaworzno” and Wesoła” coalmines possess large specific surface and great porosity and belong to coal group of “loose” spatial structure. Regarding profusion of sorbed ethane on disintegrated medium carbonized samples from “Pniówek”, “Zofiówka”, “Chwałowice” coalmines it can be supposed that in the process of coal disintegration, breaking their “compact’ structure occurs. Loosened structure of medium carbonized coals results in increasing accessibility of ethane particles to sorption centres both electron donors and electron acceptors which are present on hard coal surface. The surface sorption centre increase may result in formation a compact layer of ethane particles on coal surface. In the formed layer, not only the strengths of vertical binding of ethane particles with the coal surface appear but also the impact of horizontal strengths appears which forms a compact layer of sorbed ethane particles. The surface layer of ethane particles may lead to explosion.

scholarly journals The Impact of the Coexistence of Methane Hazard and Rock-Bursts on the Safety of Works in Underground Hard Coal Mines

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 128
Author(s):  
Justyna Swolkień ◽  
Nikodem Szlązak
Keyword(s):  
Rock Burst ◽  
Methane Concentration ◽  
High Energy ◽  
Hard Coal ◽  
Coal Seams ◽  
Safety Level ◽  
Methane Drainage ◽  
Innovative Methods ◽  
Hard Coal Mining ◽  
The Impact

Several natural threats characterize hard coal mining in Poland. The coexistence of methane and rock-burst hazards lowers the safety level during exploration. The most dangerous are high-energy bumps, which might cause rock-burst. Additionally, created during exploitation, safety pillars, which protect openings, might be the reason for the formation of so-called gas traps. In this part, rock mass is usually not disturbed and methane in seams that form the safety pillars is not dangerous as long as they remain intact. Nevertheless, during a rock-burst, a sudden methane outflow can occur. Preventing the existing hazards increases mining costs, and employing inadequate measures threatens the employees’ lives and limbs. Using two longwalls as examples, the authors discuss the consequences of the two natural hazards’ coexistence. In the area of longwall H-4 in seam 409/4, a rock-burst caused a release of approximately 545,000 cubic meters of methane into the excavations, which tripled methane concentration compared to the values from the period preceding the burst. In the second longwall (IV in seam 703/1), a bump was followed by a rock-burst, which reduced the amount of air flowing through the excavation by 30 percent compared to the airflow before, and methane release rose by 60 percent. The analyses presented in this article justify that research is needed to create and implement innovative methods of methane drainage from coal seams to capture methane more effectively at the stage of mining.

The Impact of Predried Lignite Cofiring With Hard Coal in an Industrial Scale Pulverized Coal Fired Boiler

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Halina Pawlak-Kruczek ◽  
Robert Lewtak ◽  
Zbigniew Plutecki ◽  
Marcin Baranowski ◽  
Michal Ostrycharczyk ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Bituminous Coal ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Industrial Scale ◽  
Hard Coal ◽  
Cfd Simulations ◽  
Reference Case ◽  
The Impact

The paper presents the experimental and numerical study on the behavior and performance of an industrial scale boiler during combustion of pulverized bituminous coal with various shares of predried lignite. The experimental measurements were carried out on a boiler WP120 located in CHP, Opole, Poland. Tests on the boiler were performed during low load operation and the lignite share reached over to 36% by mass. The predried lignite, kept in dedicated separate bunkers, was mixed with bituminous coal just before the coal mills. Computational fluid dynamic (CFD) simulation of a cofiring scenario of lignite with hard coal was also performed. Site measurements have proven that cofiring of a predried lignite is not detrimental to the boiler in terms of its overall efficiency, when compared with a corresponding reference case, with 100% of hard coal. Experiments demonstrated an improvement in the grindability that can be achieved during co-milling of lignite and hard coal in the same mill, for both wet and dry lignite. Moreover, performed tests delivered empirical evidence of the potential of lignite to decrease NOx emissions during cofiring, for both wet and dry lignite. Results of efficiency calculations and temperature measurements in the combustion chamber confirmed the need to predry lignite before cofiring. Performed measurements of temperature distribution in the combustion chamber confirmed trend that could be seen in the results of CFD. CFD simulations were performed for predried lignite and demonstrated flow patterns in the combustion chamber of the boiler, which could prove useful in case of any further improvements in the firing system. CFD simulations reached satisfactory agreement with the site measurements in terms of the prediction of emissions.

scholarly journals Socio-economic Factors Influencing the Development of Renewable Energy Production Sector in Poland

2021 ◽  
Vol 24 (1) ◽  
pp. 38-54
Author(s):  
Tadeusz A. Grzeszczyk ◽  
Waldemar Izdebski ◽  
Michał Izdebski ◽  
Tadeusz Waściński
Keyword(s):  
Renewable Energy ◽  
Energy Production ◽  
Hard Coal ◽  
Economic Factors ◽  
Eu Law ◽  
Factors Influencing ◽  
Level Ii ◽  
Renewable Energy Production ◽  
The Impact ◽  
Socio Economic Factors

Poland is not one of the leaders in the use of renewable energy sources (RES), and most energy is still produced using hard coal and lignite. Therefore, there are noteworthy emissions of air pollution (including ashes and greenhouse gases), and the Polish energy sector is characterized by a substantial degree of carbonization, which, as a result, threatens to expressively increase the costs of electricity production, leading to financial penalties imposed by the EU. The aim of this paper is to analyze socio-economic factors influencing the development of the RES sector in Poland. According to this aim, expert research was carried out, in which the factors influencing development potential of RES were assessed at two levels (level II – 5 factors, level III – 15 factors) according to the factor tree analysis. Based on the analysis of the level II factors, it can be concluded that the development of the RES sector in Poland will depend to a decisive extent on factors such as: EU decisions and Polish legislation affecting the development of the RES sector in Poland, prices and availability of conventional energy carriers. Other two factors – regional policy on ecology and ecological awareness in Poland – have so far little impact on the development of this sector in the state. The analysis of the level III factors shows that the greatest impact on the development of the RES sector in Poland is the influence of European lobbying of manufacturers of machinery and equipment for renewable energy production on EU law, the impact of Polish lobbying of conventional energy producers on Polish law in the production of renewable energy and the influence of European lobbying of renewable energy producers into EU law.

scholarly journals Evaluating the Potential for Combustion of Biofuels in Grate Furnaces

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1951 ◽  
Author(s):  
Małgorzata Wzorek
Keyword(s):  
Sewage Sludge ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Biomass Combustion ◽  
Municipal Sewage Sludge ◽  
Hard Coal ◽  
Meat And Bone Meal ◽  
Bone Meal ◽  
Coal Slime ◽  
The Impact

The paper assesses the impact of combustion of biofuels produced based on municipal sewage sludge in stoker-fired boilers on the amount of pollutant emissions and examines the tendency of ash deposition of biofuels formed during the combustion process. The combustion tests were performed in a laboratory system enabling simulation of a combustion process present in stoker-fired boilers. The study was conducted for three types of biofuels; i.e., fuel from sewage sludge and coal slime (PBS fuel), sewage sludge and meat and bone meal (PBM fuel) and fuel based on sewage sludge and sawdust (PBT) with particle size of 35 mm and 15 mm. This paper describes and compares the combustion process of biofuels with different granulation and composition and presents the results of changes in emission values of NOx, SO2, CO, and CO2. The emission results were compared with the corresponding results obtained during combustion of hard coal. The results showed that biofuels with lower particle sizes were ignited faster and the shortest ignition time is achieved for fuel based on sewage sludge and coal slime-PBS fuel. Also, the highest NO and SO2 emissions were obtained for PBS fuel. During the combustion of fuel based on sewage sludge and meat and bone meal (PBM), on the other hand, the highest CO2 emissions were observed for both granulations. Biofuels from sludge show a combustion process that is different compared to the one for hard coal. The problems of ash fouling, slagging, and deposition during biofuels combustion were also identified. The tendency for ash slagging and fouling is observed, especially for fuel from sewage sludge and meat and bone meal (PBM) and fuel based on sewage sludge and sawdust (PBT) ashes which consist of meat and bone meal and sawdust which is typical for biomass combustion.

scholarly journals Testing of Confining Pressure Impacton Explosion Energy of Explosive Materials

2017 ◽  
Vol 62 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Jan Drzewiecki ◽  
Jacek Myszkowski ◽  
Andrzej Pytlik ◽  
Mateusz Pytlik
Keyword(s):  
Occupational Safety ◽  
Initial Pressure ◽  
Confining Pressure ◽  
Hard Coal ◽  
Test Results ◽  
Explosive Materials ◽  
Hard Coal Mining ◽  
Explosive Charges ◽  
Pressure Changes ◽  
The Impact

Abstract This paper presents the results of testing the explosion effects of two explosive charges placed in an environment with specified values of confining pressure. The aim of this study is to determine the impact of variable environmental conditions on the suitability of particular explosives for their use in the prevention of natural hazards in hard coal mining. The research results will contribute to improving the efficiency of currently adopted technologies of natural hazard prevention and aid in raising the level of occupational safety. To carry out the subject matter measurements, a special test stand was constructed which allows the value of the initial pressure inside the chamber, which constitutes its integral part, to be altered before the detonation of the charge being tested. The obtained characteristics of the pressure changes during the explosion of the analysed charge helped to identify the work (energy) which was produced during the process. The test results are a valuable source of information, opening up new possibilities for the use of explosives, the development of innovative solutions for the construction of explosive charges and their initiation.

scholarly journals Testing the Impact of Braking Algorithm Parameters on Acceleration and Braking Distance for a Suspended Monorail with Regard to Acceptable Travel Speed in Hard Coal Mines

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7275
Author(s):  
Jerzy Świder ◽  
Kamil Szewerda ◽  
Krzysztof Herbuś ◽  
Jerzy Jura
Keyword(s):  
Numerical Simulations ◽  
Coal Mines ◽  
Travel Speed ◽  
Hard Coal ◽  
Speed Limit ◽  
Emergency Braking ◽  
Increased Risk ◽  
Braking Distance ◽  
Braking Force ◽  
The Impact

Increasing the maximum speed limit of suspended monorails, which became a very popular means of auxiliary transport, is one of the aspects of improving the efficiency of work in underground coal mines. It is especially important to enable higher (than allowed by the law) travel speed, when moving the crew to and from the workplace, which is often very distant from the shaft, and can take more than one hour of travel. Increasing this speed will make it possible to extend the effective working time of miners, which should have a positive impact on the economics of the mine. However, driving at a higher speed is also associated with increased risk of a negative impact of dynamic overload to people, e.g., during emergency braking of the suspended monorail. The concept of sequential emergency braking was developed in order to avoid excessive deceleration affecting passengers and the operator of the monorail, as well as to minimize the dynamic loads acting on the rail suspensions and on the roadway support frames, which could cause serious accidents. The developed assumptions with regard to the new method of braking are innovative in the area related to hard coal mining, where there are currently no such solutions. According to the principles of the developed concept, the total braking force was divided into two stages. The activation of the second stage depends on the deceleration measured after the time delay from activation of the first stage of braking. We present the results of the numerical simulations, which aimed to analyze the impact of changing the parameters of the braking algorithm on the braking deceleration, the braking time, and the braking distance. The possibility of changing the braking force and downward emergency braking on a high inclination angle were also taken into account during the numerical simulations. Use of the developed emergency braking algorithm enables the optimization of this process at a higher speed than is currently used. This aspect is also very important in increasing the safety for people travelling at a higher speed limit. The numerical simulations provide knowledge for safety in terms of the dynamic overload during emergency braking, without injury risk to miners or damage to equipment.

scholarly journals The Use of Selected Landscape Metrics to Evaluate the Transformation of the Rural Landscape as a Result of the Development of the Mining Function—A Case Study of the Puchaczów Commune

2021 ◽  
Vol 13 (21) ◽  
pp. 12279
Author(s):  
Sylwia Barwicka ◽  
Małgorzata Milecka
Keyword(s):  
Comparative Analysis ◽  
Land Cover ◽  
Landscape Metrics ◽  
Rural Areas ◽  
Agricultural Land ◽  
Diversity Index ◽  
Rural Landscape ◽  
Hard Coal ◽  
Landscape Indicators ◽  
The Impact

Landscape metrics have been used for years in research on the evolution of landscapes. They are also important in the process of monitoring changes taking place in the functional and spatial structure of rural areas. The main aim of this article is to assess the transformation of the rural landscape of the Puchaczów commune, which is based on a comparative analysis of selected landscape metrics. In the Puchaczów commune, due to the availability of raw materials, a mining industry has developed, which has a decisive influence on the development of the region. The study included schemes of the commune’s land cover from four periods: the pre-war period, the 1960s and the 1970s (i.e., shortly before the construction of the hard coal mine), 1990–2000, and 2020. Then, for the given time frames, with the help of the FRAGSTATS version 4.2 program, the following landscape indicators were calculated: the percentage of the landscape coverage by particular land cover units, the number of patches, the mean class area, the Shannon diversity index, and the Simpson diversity index. A comparative analysis of landscape metrics showed that the landscape of the Puchaczów commune was constantly transformed in the years 1937–2020. Despite the decrease in the area of agricultural land, agricultural production remains the dominant function of the commune. The percentage of industrial areas is the smallest, but the metric values do not reflect the enormous environmental impact of the mine. A broader description of the changes taking place in the landscape of the Puchaczów commune can therefore be obtained only by combining research with the use of landscape metrics and analyses of the impact of land cover units on the environment.

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